def fibonacciSum(n):
    if n < 2:
        return 1
    else:
        return fibonacciSum(n-1)+fibonacciSum(n-2)
n = int(input("请输入一个数"))
s = 0
for i in range (n+1):
    s=s+fibonacciSum(i)

print(s)


def fibonacciSum(n):
    if n <= 2:
        return 1
    else:
        return fibonacciSum(n-1)+fibonacciSum(n-2)
m=eval(input("请输入一个数"))
print(fibonacciSum(m))